The present invention, in some embodiments thereof, relates to methods and systems of imaging and, more particularly, but not exclusively, to methods and systems of spectral imaging using optical fibers.
Sub-millimeter diameter endoscopes are being examined for usage in many clinical applications that require minimal tissue damage. The harsh size constraints result with reduction of the number of imaging fibers in fiber bundle endoscopes and limit the frame rate of lateral scanning single optical-fiber probes. Recently, a new method termed spectrally encoded endoscopy (SEE) was introduced, utilizing a single optical fiber and miniature diffractive optics to encode transverse reflections from a sample, see Tearney, G. J., M. Shishkov, and B. E. Bouma, Spectrally encoded miniature endoscopy. Opt. Lett., 27(6): p. 412-414, 2002 and Yelin, D., et al., Three-dimensional miniature endoscopy. Nature, 443(7113): p. 765-765, 2006, which is incorporated herein by reference. Since rapid lateral scanning is not required, SEE uses slow axis scanning by probe rotation, and is thus capable of high quality imaging through ultra-miniature, single fiber endoscopic probes.
SEE is capable of imaging through ultra-miniature flexible endoscopic probes by encoding transverse reflections which are propagated, via a single optical fiber and miniature diffractive optics, from an imaged object, such as an intrabody surface or an organ. Using low coherence interferometry, recent works have demonstrated that SEE is capable of video rate, three-dimensional imaging of surface and subsurface tissue structures, as well as Doppler imaging of acoustic vibrations and flow, see for example any of the following references which are incorporated herein by reference: Tearney, G. J., M. Shishkov, and B. E. Bouma, Spectrally encoded miniature endoscopy. Opt. Lett., 27(6): p. 412-414, 2002; Yelin, D., et al., Three-dimensional miniature endoscopy. Nature, 443(7113): p. 765-765, 2006; Yelin, D., et al., Spectral-domain spectrally encoded endoscopy. Optics Express, 15(5): p. 2432-2444, 2007; Yelin, D., B. E. Bouma, and G. J. Tearney, Volumetric sub-surface imaging using spectrally encoded endoscopy. Optics Express, 16(3): p. 1748-1757, 2008; Yelin, D., et al., Doppler imaging using spectrally encoded endoscopy. Optics Express, 16(19): p. 14836-14844, 2008; and van Engen, A. G., S. A. Diddams, and T. S. Clement, Dispersion Measurements of Water with White-Light Interferometry. Appl. Opt., 37: p. 5679-5686, 1998.